With the universal popularity of the large touch-screen mobile phones, user demands for handwriting pen are also growing, meanwhile, the functional requirements for the handwriting pen is also becoming more diverse.
In public places, in order not to disturb other people, users often need to wear an earphone to use the phone's entertainment functions such as audio and video. However, the earphone must be carried separately from the phone due to its shape, and many users do not want to have the trouble of carrying an extra earphone, resulting in the earphone randomly placed due to the lack of use in a long term, and the user cannot find it when needed. The inventors of the invention find out that: if the earphone can be set into a portable structure integrated with the phone, it can objectively improve the phone's production costs and reduce the economic benefits of the business.